β受体阻滞剂对心肌梗死大鼠心肺复苏的影响

Effect of β- adrenergic receptor blockers on cardiopulmonary resuscitation in the rats of myocardial infarction model

目的 观察β受体阻滞剂慢性作用对心肌梗死大鼠心肺复苏的影响.方法 采用气管插管,结扎冠脉前降支制作急性心肌梗死（简称心梗）模型,随机分为假手术组（n=45）、心梗未喂药组（n=45）、心梗喂药组[美托洛尔20 mg/（kg·d）,n=45].窒息法制作大鼠心肺复苏模型.心脏停跳后给予肾上腺素,三组各分为低、中、高剂量三个亚组（肾上腺素0.02、0.04、0.06 mg/kg）,同时胸外按压及呼吸机辅助呼吸.结果 ①自主循环恢复率和心电活动恢复率：心梗未喂药组与假手术组比较,低、高剂量组明显下降（P=5.06×10-5,P=0.033）,中剂量组差异无统计学意义（P=0.054）.心梗喂药组与心梗未喂药组比较,中剂量组降低（P=0.022）,而高剂量组增高（P=0.043）.心梗喂药组组内比较,高剂量组较中剂量组明显提高（P=0.0006）.②肾上腺素用量：同组内低、中、高剂量亚组间比较差异有统计学意义（P〈0.05）,假手术组、心梗未喂药组、心梗喂药组三组同等剂量肾上腺素用量亚组间比较差异无统计学意义（P〉0.05）.③自主循环恢复时间：各亚组间比较差异无统计学意义（P〉0.05）.结论 β受体阻滞剂慢性作用影响心肌梗死大鼠的心肺复苏,增加肾上腺素剂量有可能提高自主循环恢复率.

Objective To study the effect of β -blockers on cardiopulmonary resuscitation in the rats of myocardial infarction model. Methods Male Sprague - Dawley rats were randomly divided in three groups： the pseudo- operation group（ n =45） , the myocardial infarction group without metoprolol （n = 45 ）, the myocardial infarction group with metoprolol （n ： 45 ） [ 20 rag/（ kg · d） ]. The left coronary artery was ligated near its origin to establish the acute myocardial infarction model. Asphyxial cardiac arrest was induced by clamping the endotracheal tube four weeks later. Each group was divided into three sub -groups according to epinephrine doses used in cardiopulmonary resuscitation： low dose group（0.02 mg/kg） , medium dose group （ 0.04 mg/kg ） , high dose group （ O. 06 mg/kg ）. Results ① Return of spontaneous circulation （ ROSC ） and return of cardiac electrical activity （ ROCEA ） ： compared with pseudo - operation group, the ROSC and ROCEA in low and high dose sub - group from the myocardial infarction group without metoprolol decreased （ P = 5.06 × 10 ^-5, p = 0. 033 ） , whereas those in the medium sub- group had no difference （P = 0. 054 ）. Compared with the myocardial infarction group without metoprolol, the ROSC and ROCEA in the medium dose sub - group from the myocardial infarction group with metoprolol decreased （ P = 0. 022 ） , whereas those in the high sub - group increased （P =0.043）. In the myocardial infarction group with metoprolol, the ROSC and ROCEA in the high dose sub- group were higher than those in the medium sub -group （P = 0. 0006）. ②Totalepinephrine dosage ： the total epinephrine dosages in low, medium and high sub - groups from one group had significant difference （ P 〈 0.05 ） , but there were no differences between the same dosage sub - group from the different groups （P 〉 0.05 ）. ③Reeovery time of ROSC （RT） ： there were no differences in RT between each sub -group. Conclusion For myocardial infarction rats with β -adrenergic receptor blockers, a higher dose for epinephrine on asphyxial cardiac arrest would improve ROSC significantly.